34 MASS. EXPERIMENT STATION BULLETIN 382 



Cuttings of Rhododendron mucronatum, R. pulchrum, R. obtusum, and R. 

 yedoense var. poukhanense will root at almost any time (9), but cuttings of 

 most azaleas, deciduous species, root best if taken in spring or early summer 

 when the wood is soft (90, 125), much less well in fall or winter (61). Best 

 rooting of cuttings of R. calcndulaceuin, R. mucronulatum, R. viscose paluni, 

 and R. canadense followed when they were taken here before rather than after 

 the middle of July. 



A good time to take cuttings of broad-leaved evergreen Rhododendrons, 

 including the named hybrids, is August (9, 77) or after the leaves on the 

 newest growth have become dark green. They have also rooted well 

 when taken in September, October, or early November (61, 77). Such 

 cuttings are made of terminal shoots, without flower buds, cut through 

 the basal ring (61). Nearing and Connors (77), using different methods, 

 successfully shorten cuttings to three inches below the lowest of the 

 three to five leaves which are left on the cutting. 



The basal cut may be made in wood of the current year in the case 

 of Indian and Kurume azaleas (9), but cuttings of other azaleas are 

 usually made with a heel (9, 61) or with the basal cut at the juncture of 

 the wood of the current and previous year (105). 



A mixture of sand and peat, 1:1 or 3:2, is a good rooting medium (9, 90), 

 better than sand (44, 88) and better than a mixture (2:1:1) of sand, peat, 

 and loam. Azalea cuttings rooted better in sand-peat which had l)een 

 previously used than in a freshly prepared mixture (44). Bottom heat 

 may benefit fall cuttings but is unnecessary for those taken in July and 

 August (9). 



Broad-leaved evergreen Rhododendrons can also be propagated, be- 

 ginning in July or when new leaves have fully developed, by leaf-bud 

 cuttings consisting of one leaf of the current year's growth, its axillary bud, 

 and an attached bit of bark and wood or piece of stem about a half inch 

 long (61, 88). This leaf-mallet type of cutting, so set as not to cover 

 any of the blade of the leaf with rooting medium, rooted in higher per- 

 centages than stem, terminal cuttings (61). Such cuttings, in sand-peat 

 at 70 to 75° F., rooted in 13 weeks without treatment or in 10 weeks after 

 treatment of the mallet or heel with indolebutyric acid (60 mg./l., 8 to 

 24 hr.) (89). Leaf-bud cuttings of the variety purpureum elegans rooted 

 100 percent in 15 weeks with treatment (indolebutyric acid 120 mg./l., 20 

 hr.), 88 percent in 18 weeks without it (90). 



Rhodotypos scandens. Softwood, late spring, cuttings root well. Taken here 

 in late May, they rooted 86 percent in sand in 8 weeks witliout treatment, 

 100 percent in 3 weeks after treatment with indolebutyric acid (25 mg./l., 

 24 hr.). Late June cuttings rooted 84 percent in 7 weeks after treatment 

 with indolebutyric acid (1:1000, in talc), not at all meanwhile without 

 treatment (104). 



Rhus, sumac. Untreated July cuttings of fragrant sumac rooted 80 to 100 

 percent in sand-peat, less well in sand (66). Cuttings of staghorn sumac and 

 smoke-tree {Cotinus Coggygria or Rhus Cotinus) are taken in England (80) 

 in late summer, but smoke-tree is not readily propagated by cuttings (73). 



Ribes. Garden currant can be propagated by September or October cuttings 

 set in the field, the upper bud level with the soil surface, and given a 

 protective mulch in winter (121). That and other species can also be 

 propagated by summer cuttings. July cuttings of European black cur- 

 rant, alpine currant (44), and northern red currant (65) rooted well. 

 Gooseberry cuttings may root less readily (5, 105), but untreated cuttings. 



